Structure and development of the upper haustorium in the parasitic flowering plant Cuscuta japonica (Convolvulaceae)
Structure and development of the upper haustorium in the parasitic flowering plant Cuscuta japonica (Convolvulaceae)
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DOI：
10.3732/ajb.94.5.737
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发表时间：
2007-05-01
影响因子：
3
通讯作者：
Lee, Kyu Bae
中科院分区：
文献类型：
--
作者：
Lee, Kyu Bae
对生长在凤仙花上的全寄生被子植物秋葵吸器的解剖和超微结构发育进行了研究。光生寄生苗的茎尖与寄主接触后，上层吸器（寄主器官外）的发育经历了吸器初始阶段、分生组织阶段和寄生茎皮层中层内内生原质（EP）三个连续阶段。吸器初始细胞具有丰富的淀粉淀粉体和线粒体，膜间空间扩大。分生组织细胞有许多大的叶绿体和发育良好的类囊体，反映了光合作用的能力。通常，所有三个阶段的吸器细胞都有明显的大细胞核，核仁增大，细胞质致密，包括许多其他细胞器，表明代谢非常活跃。在上部吸器发育的最后阶段，分生组织细胞分化为EP，这是一种穿透宿主的组织。原基近端有较小的锉状细胞，远端有细长的指状细胞。弓形细胞分裂活跃，而指状细胞含有丰富的叶绿体、双胞体、粗糙的内质网和其他细胞器，这表明EP在细胞组织学上组织良好，可以渗透到宿主组织中。
The anatomical and ultrastructural development of the haustorium of the Cuscuta japonica, a holoparasitic angiosperm, growing on the host plant Impatiens balsamina was studied. After the shoot tips of light-grown parasite seedlings contacted the host, the upper haustorium (external to the host organ) developed through three main successive stages of the haustorial initials, the meristem, and the endophyte primoridium (EP) within the middle layer of the cortex of the parasite stem. The haustorial initial cells were characterized by abundant starch-bearing amyloplasts and mitochondria with an expanded intermembrane space. The meristem cells had numerous large chloroplasts with well-developed thylakoids, reflecting the capability for photosynthesis. Commonly, all three stages of haustorial cells contained conspicuous, large nuclei with enlarged nucleoli and dense cytoplasm including many other organelles, indicating a very active metabolism, In the final stage of upper haustorium development, the meristem cells differentiated into the EP, a host-penetrating tissue. The primordium had smaller file cells at the proximal end and elongate digitate cells at the distal end. The file cells divided actively, while the digitate cells contained abundant chloroplasts, dictyosomes, rough endoplasmic reticulum, and other organelles, suggesting that the EP was cytohistologically well organized for penetration into the host tissue.